Lock stitch zigzag sewing machine



Oct. 8, 1963 E. H. DOERNER LOCK STITCH ZIGZAG SEWING MACHINE 4 Sheets-Sheet 1 Filed May 12, 1961 INVEN TOR. ERNEST H. DOERNER Oct. 8, 196 E. H. DOERNER LOCK STITCH ZIGZAG SEWING momma:

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LOCK STITCH ZIGZAG SEWING MACHINE 4 Sheets-Sheet 3 v Filed May 12, 1961 IN VEN TOR. ERNEST H. DOERNER Hum- ZagM 2 /3 ITNESS TORNEY waag l Oct. 8, 1963 E. H. DOERNER LOCK STITCH ZIGZAG SEWING MACHINE 4 Sheets-Sheet 4 Filed May 12, 1961 ERNEST H. DOERNER BY W2 TTORNEY WITNESS United States Patent Ofiice hid-5,176 Patented Oct. 8, 1963 3,106,176 LGCK STITCH ZIGZAG SEWING MACHINE Ernest H. Doerner, Morris Plains, N.J., assignor to The Singer Qompany, a corporation of New Jersey Filed May 12, 1%1, Ser. No. 109,543 Claims. (Cl. 112158) This invention relates to a look stitch sewing machine having mechanism for replenishing the supply of under or bobbin thread on the bobbin in place in the loop-taker during interrelated lock stitch forming motions of the needle and loop-taker. More particularly, this invention relates to the novel combination of an under or bobbin thread replenishing mechanism of the above character in a zigzag sewing machine.

It is an object of this invention to provide a sewing machine having a needle jogging mechanism, and thus adapted for zigzag sewing, with a bobbin thread replenishing mechanism and with means for suspending the jogging of the needle during operation of the bobbin thread replenishing mechanism.

Another object of this invention is to provide a control mechanism for initiating and terminating the operation of the bobbin replenishing mechanism of a sewing machine, which control mechanism is simultaneously eifective to suspend the lateral jogging of the needle of a zigzag sewing machine during operation of the bobbin replenishing mechanism.

Still another object of this invention is to provide a means for rendering ineffective the needle jogging mechanism of a zigzag sewing machine and for constraining the needle to reciprocate endwise in a fixed path during operation of the bobbin thread replenishing mechanism.

With the above and other objects and advantages in 'view as will hereinafter appear, this invention comprises the devices, combination, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a side elevational view of a sewing machine having this invention applied thereto with portions of the sewing machine bracket arm and mechanism therein broken away,

FIG. 2 is a vertical cross-sectional view of the free extremity of the bracket arm of the sewing machine of FIG. 1 taken substantially along line 2-2 of FIG. 1,

FIG. 3 is an enlarged vertical cross-sectional view taken substantially along line -33 of FIG. 1 illustrating the control mechanism in the sewing machine standard in a position of the parts suitable for sewing,

FIG. 4 represents a detached view of the feed lift pitman and a fragment of the tension release and zigzag throw out control member of FIG. 3 but with these parts illustrated in the position occupied during bobbin replenishment,

FIG. 5 is an enlarged horizontal cross-sectional view of the control mechanism and the connections thereof with mechanism within the sewing machine standard taken substantially along line 5-5 of FIG. 1 and illustrating the position of the parts during sewing,

FIG. 6 is a cross-sectional view through the control mechanism taken substantially along line 6--6 of FIG. 5 and illustrating the ratcheting device for the control mechanism,

FIG. 7 represents a detached view of the tension releasing and zigzag throw out cam and follower as shown in FIG. 6 but with these parts illustrated in the position oc cupied during bobbin replenishment,

FIG. 8 represents an enlarged top plan view of a fragment of the sewing machine bed with the throat plate removed to expose the loop-taker, and

FIG. 9 is a vertical cross-sectional view of the looptaker substantially along line 9-9 of FIG. 8.

The sewing machine to which this invention has been applied in the preferred embodiment illustrated in the drawings is substantially that illustrated and described in detail in the United .States patent of R. E. Johnson, No. 2,862,468, December 2,- 1958, which may be referred to particularly for the details of construction of the sewing machine frame, the needle bar and the needle reciprocating as well as the needle jogging mechanism, the needle thread take-up and needle thread tensioning devices, the work feeding mechanism, and the loop-taker drive.

For an understanding of the present invention, the sewing machine frame includes a work supporting bed 11, a standard 12 rising from the bed and supporting a bracket arm 13 overhanging the bed. A main shaft 14- journaled in the bracket arm is formed with a crank 15 connected by means of a drive link 16 to a needle bar 17 to reciprooate the needle bar endwise in a universally adjustable bearing 18 in the bracket arm and a similar bearing 19 in a needle jogging gate 2t pivotally mounted in the bracket arm. The crank 15 also serves to operate a needle thread take-up lever 21 which controls the needle thread extending from a conventional thread tensioning device 22 to an eye pointed needle 23 carried by the needle bar.

Driven from the main shaft 14 by a worm and worm wheel 25 is a stack of pattern earns 26, various ones or combinations of which may be sensed by a plurality of followers 27 which engage a Wobble plate 28 carried by a link 29 pivoted to the needle jogging gate 20 so as to impart jogging or zigzag motion to the needle laterally of the path of endwise reciprocating motion thereof.

The main shaft 14 is connected by means of meshing spiral bevel gears 3131 and 3232 and a shaft 33 journaled vertically in the standard to a bed shaft 34 journaled in the bed. By means of meshing bevel gears 35-35 on the bed shaft and on a loop-taker shaft 36, a loop-taker, indicated generally at '37, is imparted stitch forming motion in timed relation with the endwise recipprocation of the needle.

In the present invention the elements 14, 15, 16 and 31 to 36 which operatively connect the needle for endwise reciprocation and the loop-taker for rotation in timed relation are referred to as the drive elements. The drive elements remain operatively connected to impart what is termed interrelated stitch forming motions to needle and loop-taker during sewing as well as during replenishment of the bobbin. Even though no stitches are formed during bobbin replenishment, those motions of the needle and loop-taker which are prerequisite to lock stitch formation and are thus termed interrelated lock stitch forming motions continue during the under or bobbin thread replenishing process.

A gear 40 carried on the main shaft 14 may be associated with a pinion (not shown) on an electric driving motor, or a balance wheel 41 on the main shaft may be turned by hand or connected to any foot treadle or the like, the gear 4-0 or handwheel 4-1 representing, therefore, the actuating means for the drive elements of the stitch forming instrumentalities.

The main shaft 14 also serves to impart motion to a feed dog of a conventional four motion work feeding mechanism. The feed dog 50 works in slots in a throat plate 51 carried on the bed and is opposed by a presser foot 52 supported and spring biased downwardly from the bracket arm 13. The details of construction of the work feeding mechanism (not shown) may be of any conventional form and are preferably as disclosed in the above referenced United States Patent No. 2,862,468 wherein the rising and falling or 'feed lift motion is imparted to the feed dog by means of a feed lift rock shaft 53 journaled in the bed. A rock arm 54 on the feed lift rock shaft beneath the standard 12 carries a pivot pin 55 which may seat in one limb 56 of a T-shaped slot in a feed lift pitman 57 in the standard for operative connection therewith or may be disposed in an elongate limb 58 of the T-shaped slot as illustrated in FIG. 4 wherein the motion of the pitman will not be transferred to the feed lift rock shaft. The pitman 57 embraces a feed lift eccentric 59 fast On the main shaft 14.

The Loop-taker of the present invention differs in construction from that of the above referenced United States Patent No. 2,862,468. The loop-taker includes a cup shaped body portion oil, the peripheral rim of which is formed with an internal bearing rib 61 and with an inwardly projecting needle loop seizing beak 62. Carried Within the cupshaped loop-taker body portion is a bobbin carrier member 63 formed with a raceway 64 journaled on the bearing rib 61 of the loop taker body portion. A rotation restraining member 65 carried by the bed 11 supports a leaf spring 66 of which spaced arms 6767 oppose abutment surfaces 6863 in the bobbin carrier member 63 serving to prevent rotation of the bobbin carrier member with the loop-taker body portion and also to constrain the bobbin carrier member in place on the bearing rib 61 of the loop-taker.

The bobbin carrier member 63 is formed with a bobbin accommodating cavity 69 in which a bobbin 70 is contained. The bobbin is supported in the cavity 69 by a large top flange 71 formed on the bobbin which rests on the bobbin carrier member. A bottom flange 72 on the bobbin is of smaller diameter than the bobbin accommodating cavity 69. An axial pin 73 carried by the bobbin is embraced by a finger 74- pivoted on the bobbin carrier member by means of a fulcrum pin 7 5. The bottom flange of the bobbin is formed with a plurality of holes 76 arranged in a circle concentric with the center of the bobbin to accommodate the bobbin driving means Which will be described hereinbelow. Overlying a thread entrance slot 77 formed in the bobbin carrier member leading to the bobbin accommodating cavity is a bobbin thread tensioning spring 78 secured on the bobbin carrier member and formed with a thread guiding notch 79.

Slidable axially in the hollow loop-taker shaft 36 is a pin 80 which extends within the cup-shaped loop-taker body portion 60 and has secured thereto beneath the bo'bbin carrier member a bobbin winding member 81. The bobbin winding member carries a pin 82. disposed in registry with the plurality of holes 76 in the bobbin flange of the bobbin and is formed with a raised circular rib 83 disposed opposite the clearance space between the periphery of the bottom flange of the bobbin and the bobbin accommodating cavity 69 in the bobbin carrier member. The bobbin winding member is formed with a radial finger 84 which projects into an opening 85 in the cup-shaped loop-taker body portion rotationally to interlock the bobbin winding member 81 with the loop-taker. The bobbin winding member is also formed with an attenuated thread clamping finger 86 which underlies the rim of the looptaker body portion immediately behind the loop seizing beak 62.

The above described looptaker cooperates with the eye pointed thread carrying needle 23 to replenish under or locking thread on the bobbin and subsequently to form lock stitches using the thread replenished on the bobbin in a manner similar to that described in the copending United States patent application of Stanley J. Ketterer, Serial No. 75,3 87, filed December 12, 1960 to which reference may be had.

Briefly for an understanding of the present invention, when the pin 80 and bobbin winding member 81 thereon is shifted toward the bobbin, the pin 32 'drivingly engages one of the holes 76 in the bobbin, the rib $3 enters the space between the bobbin and the bobbin carrier member to deflect needle thread seized by the loop seizing beak into the bobbin rather than about the bobbin which is the normal path of the seized thread loop during sewing. The attenuated clamping finger 86 behind the loop seizing beak serves to clamp the seized needle thread loop on the looptaker to assist in carrying on to the bobbin one limb Of the loop seized by the beak 62. 'ihe needle thread when introduced into the bobbin by the deflector rib S3 assumes a path conductive to admittance through the thread slot 77 in the bobbin carrier and thence beneath the bobbin thread rtensionin-g spring 78 and into the lhrcad guiding notch 79.

The pin 81 and the bobbin winding member 81 is shifted toward the bobbin by a lever 99 fulcrumcd at 91 beneath the bed 11 and having secured thereto a leaf spring 92 which underlies the pin 80. A cam disk 93 fast on the pin 8i) cooperates with a follower finger 94 fixed beneath the bed to release the bobbin winding member from winding position momentarily during each rotation of the looptaker. A similar periodically operative release mechanism is described in the above referenced United States patent application No. 75,387 for the similar purpose of insuring that the needle thread be clamped back of the hook beak regardless of when winding of the bobbin is initiated in the cycle of motion of the loop-taker. For this purpose the cam disk 93 and follower finger is preferably timed to release the bobbin winding member for an instant and to reestablish the bobbin winder in operative position immediately after loop seizure by the loop seizing bea Referring to FIGS. 1 and 3, a control device for initiating replenishment of under or bobbin thread and for determining the amount of thread to be replenished is carried by a cylindrical block secured in the front wall of the sewing machine standard between the standard and an escutcheon plate 101. A shaft 102 journaled in the block 100 carries a dial 103 of which the flange 10 4 is provided with indicia 105 which may be viewed through a window 106 in the escutcheon plate. Fast on the shaft 102 within the standard is a ratchet wheel 107 and a hub 108 formed with a cam notch 109'. Loosely journaled on the shaft within the standard is a pawl carrying lever 110 to which a pair of pawls 111 are pivoted. The pawls are each biased by the springs 11-2 to play over the periphery of the ratchet wheel and \the plawls are staggered to engage the ratchet Wheel at one-half the circumferential distance between teeth on the ratchet wheel. A radially elongate slot 113 formed in the pawl carrying lever serves to accommodate a drive pin 114 on the feed lift pitman 57 to drive the shaft 162 in step-by-step increments during operation of the sewing machine drive elements. A spring 115 on the feed lift pitman yieldingly supports the drive pin relatively to the pitrnan so that a delayed engagement of the pin 114 in the slot 116 is possible if the two are not immediately in registration. The pitman 57, however, is biased by a coil spring 116 in a counterclockwise direction as viewed in FIG. 3 into a position in which the pin 55 on the feed lift rock arm is seated in the limb 56 of the slot in the pitman 57 and the drive pin 114 occupies a retracted position out of engagement with the slot 113 in the pawl carrying lever. The pawl carrying lever 116* is preferably also formed with a bifurcated portion 117 loosely embracing a pin 118 set into the block 100 for the purpose of maintaining the pawl carrying lever generally in the positions illustrated in FIG. 3.

Fullcrumed on a pin 120 set into the block 1% is a control lever 121 formed with a shoulder 1-22 abutting the hub 108 fast on the shaft 102 and adapted to coact with the cam notch 109 as illustrated in FIGS. 6 and 7. The control lever 121 is formed with an arm 12% which overlies an arm 124 projecting from a link 1125 carried in the standard connected at the top by a pivot pin 126 to one arm of a bell crank lever 1-27 and pivoted at the bottom by a pivot pin 128 to the lever 90. As illustrated in FIGS. 3 and 4, the link 1 25 is formed with a finger 129 which abuts an inclined cam surface 130 formed along the edge of the feed lift pitman 57. When the shaft 102 is turned manually by the operator causing the cam notch 10 9 to move out of registry with the shoulder 122 of the control lever 121, the arm 1 23 on the control lever will be shifted downwardly carrying with it the arm 124 and the link 12.5. The finger 129 in traversing the inclined cam surface 130 will shift the pitman 57 to the position illustrated in FIG. 4. In this position, the feed lift rock arm is disconnected from the feed lift pitman, and the drive pin 114 is shifted against the pawl carrying lever so as to be urged into the slot 113 thereof by the spring 115 when the pin first registers with the slot 113. Depression of the link 125 will also turn the lever 90 to shift the bobbin winding member 81 into effective position to replenish the bobbin. The control lever 121 is preferably formed with a bifurcated portion 131 loosely embracing the pin 118 for the purpose of maintaining the control lever generally within the range of positions illustrated in FIGS. 3 and 4.

The turning motion of the dial 106 necessary to effect separation of the feed lift connection and engagement of the pawl driving pin 116 is approximately 20 degrees from the normal at-rest position of the dial which is indicated in FIG. 1. The normal at-rest dial position may be indicated by the indicium as illustrated and the point on the dial at which the drive pin becomes engaged may be indicated by the indicium Full to indicate that if turned to this position the bobbin will be fully wound. The dial may also be marked with numbers indicative of the approximate yardage of thread which will be wound as a result of any particular dial setting.

If the dial is turned until the position marked F appears in the window 106, then the pawls 111 and 112 will become operative to advance the ratchet wheel by one-half tooth for each revolution of the main shaft 14, that is, for each reciprocation of the needle, for the maximum duration until the dial has turned the remaining angular amount and has been returned to the position illustrated in FIG. 1. If the dial is turned by the operator beyond the point marked Full to some position short of the at-rest position, then the ratchet will be driven a correspondingly shorter number of revolutions of the main shaft 14 before reaching the at-rest position and a correspondingly smaller amount of thread will be replenished in the bobbin.

The control device described hereinabove in addition to initiating and terminating the operation of the bobbin replenishing mechanism, dropping the work feeding mechanism during bobbin replenishment and initiating as well as automatically terminating the ratchet and pawl drive for determining the duration of bobbin replenishment, serves by way of the link 125 to release the needle thread tensioning device and suspend operation of the needle jogging mechanism during bobbin replenishment.

For this purpose a link 140 is pivotally supported at one end on a pin 141 set in the bell crank 127 and at the other end on a pin 142 carried in one arm of a bell crank 143 carried in the bracket arm 13. The bell crank 143 is, in turn, connected by a pivot pin 144 to a needle thread tension release member 145 which as illustrated in FIG. 2 extends beneath a tension release lever 146 in the bracket arm which abut-s a tension release pin 147 associated with the needle thread tension device.

Formed on the link 140 in the bracket arm is an upstanding arm 150 which carries an adjustable stop screw 151 disposed adjacent to an abutment 152 formed on the link 29 of the needle jogging mechanism. When the link 125 is depressed by the control device, the link 140 in the bracket arm will be shifted to the left as viewed in FIG. 1 thus shifting the needle thread tension release member 145 to release the tension device and causing the stop screw 151 to carry the link 29 of the needle jogging mechanism to an extreme position to the left as viewed in FIG. 1 carrying and holding the wobble plate 28 out of the range of motion of the pattern cam followers 27 during replenishment of the bobbin. When the control device is returned to the at-rest position and the link is released to terminate replenishment of the bobbin and begin sewing, a coil spring 15% carried between the bracket arm and the link aids in returning the link 140 to the position illustrated in FIG. 1 wherein the needle jogging mechanism and the needle thread tension device are again rendered effective.

With this invention, a bobbin replenishing mechanism operative during continued stitch forming motion of the needle and loop-taker may be applied to a zigzag sewing machine. The bobbin replenishing operation may be initiated with work fabrics in place beneath the needle since the lateral jogging of the needle will be suspended, the work feeding mechanism will be rendered ineffective, and the needle will be constrained to move endwise in a fixed path during replenishment of the bobbin thread. As a consequence, during bobbin thread replenishing operations, the needle will repeatedly penetrate the work fabrics at the same point and thus only during the first needle penetration of the replenishing operation will a needle thread loop be presented to the loop-taker.

Having thus set forth the nature of this invention, what I claim herein is:

1. in a lock stitch sewing machine having a thread carrying needle, means for imparting endwise reciprocation to said needle, a loop taker, a bobbin journaled relatively to said loop taker, drive elements operatively connecting said loop taker and said endwise needle reciprocating means for motion in timed relation as is required for the formation of lock stitches, zigzag mechanism carried in said sewing machine for imparting motion to said needle laterally of the path of endwise reciprocatory motion of said needle, means driven by said drive elements for actuating said zigzag mechanism, means operated by said drive elements for winding a thread on said bobbin journaled in said loop taker while said endwise needle reciprocating means and said loop taker are operatively connected by said drive elements, control means for initiating and terminating operation of said winding means, and means operated by said control means for rendering said zigzag mechanism ineffective upon initiation of operation of said winding means and effective upon termination of operation of said winding means.

2. In a lock stitch sewing machine having a thread carrying needle, means for imparting endwise reciprocatory motion to said needle, a loop taker, a bobbin journaled relatively to said loop taker, drive elements operatively connecting said loop taker and said endwise needle reciprocating means for motion in timed relation as is required for the formation of lock stitches, zigzag mechanism carried in said sewing machine for imparting motion to said needle laterally of the path of endwise reciprocatory motion of said needle, means driven by said drive elements for actuating said zigzag mechanism, means operated by said drive elements for winding a thread on said bobbin journaled in said loop taker while said endwise needle reciprocating means and said loop taker are operatively connected by said drive elements, control means for initiating and terminating operation of said winding means, means operated by said control means for rendering said zigzag mechanism ineffective and for constraining said needle against zigzag motion laterally of the path of endwise reciprocatory motion of the needle upon initiation of operation of said winding means, and means operated by said control means for rendering said zigzag mechanism effective and for releasing said needle zigzag motion constraining means upon termination of operation of said winding means.

3. In a lock stitch sewing machine having a thread carrying needle, means for imparting endwise reciprocatory motion to said needle, a loop taker, a bobbin journaled relatively to said loop taker, drive elements operatively connecting said loop taker and said endwise needle reciprocating means for motion in timed relation as is required for the formation of lock stitches, zigzag mecha- 'sm carried in said sewing machine for imparting motion to said needle laterally of the path of endwise reciprocatory motion of said needle, means driven by said drive elements for actuating said zigzag mechanism, means operated by said drive elements for winding a thread on said bobbin journ aled in said loop taker While said endwise needle reciprocating means and said loop taker are operatively connected by said drive elements, control means for initiating and terminating operation of said winding means, throw-cult means for rendering said zigzag mechanism ineffective to impart motion to said needle laterally f the path of endwise reciprocatory motion of said needle, and means operated by said winding control means for operating said zigzag throw-out means during operation of said winding means.

4. In a lock stitch sewing machine having a thread carrying needle, means for imparting endwise reciprocatory motion to said needle, a loop-taker, a bobbin journaled relatively to said loop-taker, drive elements operatively connecting said loop-taker and said endwise needle reciprocating means for motion in timed relation as is required for the formation of lock stitches, zigzag mechanism carried in said sewing machine for imparting motion to said needle laterally of the path of endwise reciprocatory motion of said needle, means driven by said drive elements for actuating said zigzag mechanism, a work feeding mechanism carried in said sewing machine, means driven by said drive elements for actuating said work feeding mechanism, means operated by said drive elements for winding a thread on said bobbin journaled in said loop taker while said endwise needle reciprocating means and said loop-taker are operatively connected by said drive elements, control means for initiating and terminating openation of said winding means, and means operated by said control means for rendering said zigzag mechanism and said work feeding mechanism simultane- 5% ous ly ineffective upon initiation of operation of said winding means and for rendering said zigzag mechanism and said work feeding mechanism simultaneously efiective upon termination of operation of said winding means.

5. In a look stitch sewing machine having a thread carrying needle, means for directing a thread to said thread carrying needle including a thread tensioning device, means for imparting endwise reciprocation to said needle, a loop-taker, a bobbin journa led relatively to said loop-taker, dnive elements operatively connecting said loop-taker and said endwise needle reciprocating means for motion in timed relation as is required for the formation of lock stitches, zigzag mechanism carried in said sewing machine for imparting motion to said needle laterally of the path of endwise reciprocatory motion of said needle, means driven by said drive elements for actuating said zigzag mechanism, means operated by said drive elements for winding a thread carried by said thread carrying needle on said bobbin journaled in said loop-taker while said endwise needle reciprocating means and said loop-taker are operatively connected by said drive elements, control means for initiating and terminating operation of said winding means, and means operated by said control means for rendering s aid zigzag mechanism and said thread tensioning device simultaneously ineffective upon initiation of operation of said wind ing means and simultaneously effective upon termination of operation of said winding means.

References Cited in the file of this patent UNITED STATES PATENTS 1,100,441 Ohlson June 16, 1914 1,394,075 Finch Oct. 18, 1921 1,794,255 Stephenson Feb. 24, 1931 FOREIGN PATENTS 517,363 Italy Feb. 28, 1955 1,224,744 France June 27, 1960 

1. IN A LOCK STITCH SEWING MACHINE HAVING A THREAD CARRYING NEEDLE, MEANS FOR IMPARTING ENDWISE RECIPROCATION TO SAID NEEDLE, A LOOP TAKER, A BOBBIN JOURNALED RELATIVELY TO SAID LOOP TAKER, DRIVE ELEMENTS OPERATIVELY CONNECTING SAID LOOP TAKER AND SAID ENDWISE NEEDLE RECIPROCATING MEANS FOR MOTION IN TIMED RELATION AS IS REQUIRED FOR THE FORMATION OF LOCK STITCHES, ZIGZAG MECHANISM CARRIED IN SAID SEWING MACHINE FOR IMPARTING MOTION TO SAID NEEDLE LATERALLY OF THE PATH OF ENDWISE RECIPROCATORY MOTION OF SAID NEEDLE, MEANS DRIVEN BY SAID DRIVE ELEMENTS FOR ACTUATING SAID ZIGZAG MECHANISM, MEANS OPERATED BY SAID DRIVE ELEMENTS FOR WINDING A THREAD ON SAID BOBBIN JOURNALED IN SAID LOOP TAKER WHILE SAID ENDWISE NEEDLE RESIPROCATING MEANS AND SAID LOOP TAKER ARE OPERATIVELY CONNECTED BY SAID DRIVE ELEMENTS, CONTROL MEANS FOR INITIATING AND TERMINATING OPERATION OF SAID WINDING MEANS, AND MEANS OPERATED BY SAID CONTROL 